Scroll-sawing machine



l(No Model.)

D. W. PERRY.

SCROLL SAWING MACHINE.

s Patented Jul 21, 1885. lp: Y

e e Y INVENTU'R..

AUNITED STATES PATENT 'sl-OFFICE.

DANIEL IV. PERRY, OF HARRISBURG, PENNSYLVANIA.

SCROLL-SAWING MACHINE.

SPECIFICATION forming part of Letters Patent No. 322,748, dated J'uly 21, 1885.

Application filed February 12, 1885.

To aZZ whom it may concern:

Be it known that I, DANIEL' W. PERRY, a citizen of the United States of America, residing at Harrisburg, in the county of Dauphin and State of Pennsylvania, have invented certain new and useful Improvements in Sawi ng-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

The object of my invention is to avoid inequality of strain or tension upon the saw occasioned by subjecting, as heretofore practiced, the saw to a single usually upward pull or strain, and to equalize the strain upon the upward and downward strokes of the pitman, which inequality of strain produces a concussion or thud at the end of each stroke of the saw, thus shaking or vibrating the table, it being next to impossible to secure sufficient rigidity of strain or tension to overcome the difference of momentum between the upward and downward strokes of the pitman when the entire strain is maintained or applied at one end or in one direction. A

Further objects of my invention are to prevent the transmittal of the vibrations or concussions resulting from the action ofthe driving-shaft to the work or saw table, permitting of the performance of bet-ter work, and to produce a smooth-running saw and one capable of being driven at a high speed. y

To these ends my invention consists, broadly, in subjecting both ends of the saw to strain or tension and in supporting the driving-pulley shaft independently ofthe worktable or the frame of the latter, substantially as hereinafter fully described and claimed.

In the accompanying drawings, Figure l is a side elevation of my improved sawing-machine. Fig. 2 is a sectional elevation thereof, and Fig. 3 is a detail View of my invention.

In the embodiment of my invention I make use of the ordinary work-table, A, together with its supporting-frame a. Mounted upon said table at one side is a bracket, B, having a hollow arm, b, with its lower side open and overhanging the table, the function of which will appear further on.

Below the table A, I dispose and secure independently of the latter a separate frame, C,

(No model.)

upon lower cross-pieces of which is supported the boxing d of the driving-shaft D, carrying the fixed and loose pulleys e e upon one end and the eccentric f at the other end. By thus supporting the driving-shaft intact with thework-table and its frame or legs the concussions or vibrations arising from the action of said shaft are prevented from being transmitted to the work-table, permitting the performance of the work to the best possible advantage.

E is the saw, of the usual gig-pattern, having'its ends provided with retaining or holding pins g, which rest in hooks g', one bolted to a cross-head, h, connected or bolted to a pitman, F, in turn connected by a wrist-pin to the eccentric f, said ends of the saw entering slots in said hooks, whereby with the keys or pins g in place in said hooks can be readily connected to or disconnected from said hooks. The other hook is connected or bolted to a strap, i, passed into and through the open hollow arm I) of the bracket B, and connected to a spring, G. The outer end of the spring G is coupled or connected by a bolt, j, to the outer end of a second spring, G', bolted or fastened to a cross-bar within said open hollow arm b, whereby the saw is stra-ined or put under tension from its upper end.

To the spring G is connected one end of a screw-rod, le, which passes through an upper crossbar of said arm b, and is encircled by a spring, 7c. Said rod la is provided above its said spring with a nut to more or less compress and vary the tension of said spring to accordingly effect the tension of the spring G. The saw is also put under tension or strain from its lower end by the action of a spring, H, one end of which spring is connected or coupled by a bolt, Z, to a second spring, H', fastened or bolted to an upper cross-piece of an open hollow arm, C', of the frame C. The opposite end of the spring H is connected by a flexible strap, m, to the wrist-pin connecting the pitman F to the cross-head 7L. It will Vbe noticed that while the upper spring or springs are adapted to exert upward pressure or strain upon the saw-blade the lower spring or springs are designed to exert downward pressure or strain upon said saw-handle, the

by a screw-rod, n, connected to said spring and passed through a lower crossbar of the arm C', said rod being encircled by a spring, o, which is capable of being more or less compressed, to vary its tension, by a nut, o', screwed upon said rod.

Fastened to and depending from an underneath cross-piece of the work or saw table A u is a guide, h', disposed so as to guide the saw in its movement.

J is a guide, which comprises a vertical bar fitted in an apertureor channel, @at the. conjunction of the bracket B and its arm b, and a horizontal bar with its vrear edgeconnected to the lower end ofsaid vertical bar, and having at its front corner edges projections dvis-` posed alongside of Athe saw, as seen in Fig. 1. The principle upon which my invention is constructed-z'. e, by applying opposite strain or tension to both ends of the saw-blade, as

above described, the strain is distributed upon the upward and downward strokes of the saw-is based` upon thefact that if the strain all be applied to .one end of the saw-blade, which strain is usually applied at the upper end, the upward stroke will receive a inomentum equal to `the numberof poundsrof strain required tostiffen ythe blade, whereby an inequality in the movement of the blade in its upward and downward strokes will follow lthe upward stroke, being yery rapid because of the great momentum thus produced. For example, it being assumed that only onespring is used-fi. e., strain applied tothe upper end of thevblade--say that it requires twenty (20) pounds strain to stiffen the blade, that the downward stroke involves, say, five (5) pounds force to effect the cut, and that the weightof the pitman, say, is three (3) pounds, it will thus be seen that a downward c ut will require apressure orforce of twenty plus iive (5) lessthree (3) equals twenty-two (22) pounds, while-the upward stroke, withno resistance to overcome savethe-weight of the pitman, but lwhich yis simply to return the blade to again effect the cutting operation, `is only-lessened three (3) pounds, theweightof thepitman thereby wasting nineteen (19) pounds of `pressure or force, and consequently requiring the overcoming of a rapidmomentum of seventeen (17 pounds. XVith the saw running at the rate ofA eight hundred (800) strokes per minute -it would be necessary toovercome a force equal to seventeen (17) pounds eight hundred (800) equals thirteen thousand land six hundred (13,600)

ypounds weight forevery minute, and for a days work of ten hours it would require the movement of nine million and one hundred and twenty thousand (9,120,000) pounds through a space equal to the stroke of the saw, which is wasting a great deal of unnecessary force, producing an inequality of momentum in the downward and upward stroke of the saw, which inequality or difference of momentum exceeds the power exerted by the spring twenty (20) pounds and the resistance of cut iive (5) pounds less weight of pitman three (3) pounds equals twentyitwo (22) pounds, plus spring above twenty (20) pounds, making a total difference of forty-two (42) pounds on each stroke vof the saw. By myimprovement there may be an almost exact amount of momentum maintained on up and downmotion ofthe saw.

.Further advantages of myinventionare that a smooth-running saw is obtained and one capable of being run ata veryhigh speed arising from the aforesaiddisposition of. theworktable and frame independently of thesaw-supporting frame.

It will be understood that I do not confine myself tothe particular disposition ofarrange` ment ofithe parts .or to the manner shown vof supporting the upper spring-arm upon -the work-table, as vthe .same may be ,suspended v:from -theuceiling in the usual way, leaving the work orsaw table whollyfree for supporting and manipulating the work or material being sawed; nor vdo I confine myself tothe special arrangenicntor number, of springs shown;.but I do, however, Vrestrict the application of my .invention to that class of saws .operated by meansof driving-pulleys, as above specilied.

Having thus fully described .my invention, what I cl-aim,'and desire to secure vby Letters Patent, is-

The combination, with the separate frame C, disposed below and independent of the work-table, supporting on 'its lower vcrosspieces boxing for reception of the drivingshaft, ofthe bracketinounted upon one side of said table and having a hollow arm, the spring-G', secured therein and con nectedto the spring G, and-the spring H, secured in an open hollowarm, C', ofthe frame C, and the tension-regulating devices or contrivances for actingupon the springs G and H, constructed and arranged substantiallyy as shown, and for lthepurpose herein set forth.

Iutestimony whereof I ailix my signature in presence of two witnesses.

DANIEL W. PERRY. Witnesses:

FRANKLIN SANDERS, A. J. EYLER.

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